The field of printed electronics, and more generally the field of printed functional materials, represents a promising avenue toward a new world of devices ranging from flexible, low-cost computer displays to lightweight, high-capacity storage batteries. Using printing technologies traditionally associated with the creation of human-readable text or graphics, special printable compositions or “inks” are transferred to surfaces and cured into functional elements such as conductors, semiconductors, and dielectrics. Multilayer structures can be built in an additive process, i.e., by printing additional layers of elements on top of previously-cured elements, to create more complex structures such as thin-film transistors.
Although several advantages can be brought about in terms of device flexibility, cost, durability, and the like, the electrical performance offered by today's printed semiconductors is generally inferior to the performance of single-crystal semiconductors used in most of today's high-speed electronics and computing equipment. Whereas single-crystal silicon semiconductors may offer mobilities in the range of 800-1000 cm2/V-s, which can facilitate device switching speeds in the MHz and GHz range, printed semiconductor elements such as pentacene, a p-type organic semiconductor, may only offer mobilities on the order of 2-3 cm2/V-s.
One issue can arise in the fabrication of functional printed elements when the printable composition contains nanostructures intended to impart certain characteristics to the cured printed element, such as certain electrical characteristics (e.g., conductive, semiconductive, dielectric, etc.). Upon thermal treatment or other curing method, and due at least in part to a volume shrinkage of a molecular precursor accompanying the nanostructures in the printable composition, the morphology of the resulting printed element can be porous, and the surface of the resulting printed element can be rough. This, in turn, can bring about difficulty in properly printing a subsequent layer on top of the printed element. It would be desirable to provide for reduced porosity and smoother surface topography in the printed element.